1. Field of the Invention
This invention relates to an apparatus for and a method of crimping electrical terminals to obtain improved electrical continuity between a terminal and an electric wire by forming a concave portion in a crimped terminal after the electric wire has been crimped to the terminal.
2. Description of the Prior Art
There is shown, in FIGS. 6 and 7, a prior art regarding an electrical terminal crimping method disclosed in Japanese Patent Application laid-open No. 53-147992.
In the method, as shown in FIG. 6, a crimping portion 32 of a terminal 31 is provided with a plurality of small, inwardly pointing protrusions 33 and a stripped wire core portion 35 of a wire 34 is put on the crimping portion 32. Then, as shown in FIG. 7, the crimping portion 32 is inwardly compressed between a crimper (an upper die) 36 and an anvil (a lower die) 37 so that the small protrusions 32 strikes into the wire core portion 35. The small protrusions 33 serves to obtain improved electrical continuity and securer joint between the crimping portion 32 and the wire core portion 35.
However, the above-mentioned prior art has a drawback that, as shown in FIG. 8, in terminal crimping operation, the small protrusion 33 damages the wire core portion 35 by cutting wire cores 35a or that, as shown in FIG. 9, the wire cores 35a may relieve from the small protrusions so that the small protrusion 33 does not strikes appropriately into the wire core portion 35.